Self-sustaining structure



United States Patent Office 3,259,264 Patented July 5, 1966 3,259,264 SELF-SUSTAINING STRUCTURE John S. Best and Albert J. Palfey, Midland, Mich., as-

signors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Mar. 19, 1965, Ser. No. 441,274 3 Claims. (Cl. 220-4) This application is a continuation-in-part of our copending application Serial No. 123,508, filed July 12, 1961 and now abandoned.

This invention relates to a self-sustaining structure. It more particularly relates to self-sustaining structures comprised of a plurality of pane-ls for environmental control.

In the fabrication of structures for environmental control, such as cold rooms, walk-in refrigerators, and similar structures wherein a considerable degree of isolation of the space enclosed within the structure from the space surrounding the structure is required, it is conventional practice to construct a frame and fill spacing between frame members with an insulating material. Much difiiculty has been encountered in obtaining adequate service from such enclosures because of thermal and moisture leaks. In cases in conventional frame construction, the studs, joists, and rafters present a path for heat to travel in or out of the enclosure. Other thermal paths are provided by nails, screws, bolts, and similar means having relatively high thermal conductivity. Frequently the walls, ceiling, and floor of such an enclosure are not as vapor-tight as would be desired, resulting in undesirable and disadvantageous frost build up when low temperature facilities are involved or undesirable leaks and temperature irregularities and nonuniformities in such an enclosure is intended to operate above the ambient temperatures. Generally, in order to form an enclosure of sufficient resistance to moisture penetration and mechanical disruption caused by temperature differences, a considerable amount of gasketing and caulking is required. Such joints frequently fail after extended exposure to temperature cycles and often become unsatisfactory when employed at low temperatures.

It is an object of this invention to fabricate an enclosure having good thermal insulation between its interior and its exterior.

It is another object of this invention to fabricate an enclosure from a plurality of panel-like members which requires no fastening means within the walls thereof.

It is still another object of this invention to fabricate a self-sustaining insulated space which is held together by external tension members.

These benefits and other advantages are achieved in accordance with the invention by providing a self-sustaining enclosure comprising a plurality of interfitting panels so constructed and arranged so as to provide an enclosure and said panels maintained in engagement with each other by elongated external tension members disposed about the periphery of the structure and applying a compressive force thereto.

Further benefits and advantages of the invention will become more apparent when the following specification is taken in conjunction with the drawing wherein:

FIGURE 1 depicts an isometric view of an enclosure fabricated in accordance with the invention;

FIGURES 2 and 3 are a side and end view of panels employed in the fabrication of the enclosure;

FIGURE 4 is a sectional view of the enclosure of FIG- URE 1;

In FIGURE 5 there is illustrated a sectional view of FIGURE 1;

FIGURE 6 depicts an alternate configuration of a portion of a panel employed in the practice of the invention; and

FIGURE 7 shows an alternate configuration of a tension member attachment means for use in the present invention.

In FIGURE 1 there is illustrated an isometric view of an enclosure for environmental control generally illustrated by the reference numeral 10. The enclosure 10 comprises a plurality of panels. Visible in the drawing are two center panels 12, four end panels 14, and two door receiving panels 16 and 17. The panels 16 and 17 carry a door member 19. About the edges of the enclosure 10 are positioned vertical tension members 21, longitudinal tension members 23, and horizontal tension members 25. At the corners 27 of the enclosure 10 are a plurality of corner caps 28. The corner members 28 are secured by means of screws 30 to one each of the ten sion members 21, 23 and 25. The tension members are held to panels 12, 14, 16 and 17 by means of screws 32.

In FIGURE 2 there is illustrated a side view of a panel 14 having a core 36, an outer face sheet 38, and inner face sheet 39. The panel 14 defines a pair of rabbets designated by the reference numeral and the rabbet 41.

In FIGURE 3 there is illustrated an end view of the panel 14 showing a relative position of the rabbet 40, rabbet 41, and a groove 43.

FIGURE 4 is a cross-sectional view of the enclosure 10 showing the relationship between the various panels and their manner of interfitting. The floor of the enclosure comprises two panels 14, and a panel 12. The longer side walls are similarly formed. The ends of the structure are each comprised of 2 panels 16 and 17. The panels 16 and 17 and 12 and 14 are joined at their grooved edges by a plurality of splines 45. The vertical tension members 21 overlay the adjacent corners of panels 14 and 16 and 14 and 17 are formed by the overlapping of the rabbets 41.

In FIGURE 5 there is illustrated a section of the enclosure 10, illustrating the relationship of the panels 12, 14 and 17 and splines (not shown).

In FIGURE 6 there is depicted a sectional view of an alternative embodiment of a panel generally designated by the reference numeral the panel 50 has a core 51, an inner face member 53, and an outer face member 54. The core 51 defines a rabbet 55. The core 51 extends slightly beyond the face sheets 53 and 54 to provide a core protrusion 57.

In FIGURE 7 there is illustrated an exploded view of an alternate embodiment for the connection of tension members generally indicated by the reference numeral 60. The connector generally comprises a generally tetrahedral cap 62 having defined therein a plurality of openings 64 adapted to receive fastening members (not shown). Tension members 66, 67 and 68 are adapted to fit within the generally tetrahedral cap 62 and be secured thereto by fastening members through the openings 64.

In the fabrication of enclosures in accordance with the invention, a wide variety of panel members are employed. Typically and advantageously, various commercial insulating panels are adaptable to the presently contemplated structures, such as those which are formed from a pair of face sheets overlying and adhered to a cellular expanded plastic core; typical cores which are employed in such panels are those of foamed polystyrene, polyvinyl chloride foams, phenol formaldehyde foams as well as foamed glass, rigid organic and inorganic fiber mats, and the like.

Face sheets for such cores are readily fashioned from plywood, wood veneer, fiber glass, epoxy resin compositions, metal, and the like. The particular core materials and face sheet employed will depend on the application for which the enclosure is to be utilized. If the enclosure is to be subjected to moisture and periodic cleaning such as might be encountered in meat storage, advantageously,

polyester facing sheets and foamed polystyrene cores could edges of the enclosure to provide the necessary compressive force to maintain the structure in accordance with the invention in its intended position. Cable, rope, tape, and like members capable of providing a compressive force upon the enclosure are also utilized.

A preferred embodiment of the present invention is illustrated in FIGURE 1 wherein two general types of panels are employed; these are typified by the panels 12 and 14. The panel 12 is provided with a rabbet on either end and spline receiving groove 43 on either side. Thus, the panels 12 may be joined together in side by side relationship by introducing a spline 45 into the grooves 43 and a relatively rigid relationship is maintained between the two sheets. The panels 14 similarly may be joined to the panels 12 or to like panels 14 to give what effectively is a larger sheet. Generally, junctions between the sheets such as 12 when disposed at right angles to each other is accomplished by lap fitting to the terminal portions of the sheets having defined therein the rabbet 40 at right angles. Thus, the enclosure is formed by the interfitting of two basic types of panels 12 which could be designated as an end corner panel, that is, it is designed to form a corner at the ends of the panel by lapping the end portions thereof, and the other type of panel 14 is a side and corner panel wherein three sides of the panel are adapted to meet with rabbets to form walls generally normally to the plane of the panel on two ends and the side thereof. The panels designated as 16 and 17 are basically and fundamentally identical with the panel 14 with the exception that part of the panels have been removed to form an opening to carry the door 19.

By the provision of rigid fitted joints where two panels come together to form an angle and spline joints wherein panels butt together in edge to edge relationship a structure is formed which is rigid when under compression. External pressure by the corner members 27 or the alternate embodiment 60 serve to firmly force together 3 panels disposed substantially at right angles to each other. The tension members such as 23 further provide the adequate pressure to maintain the edge to edge relationship between the panels 12 and 14. It is impossible without distortion or destruction of the panel for the panels to be displaced inwardly into the space enclosed by the structure. For most applications, the tension members 23 provide sufficient and adequate pressure to maintain adequate fitting for the rabbeted ends of the panels 12. However, if relatively large structures are prepared in accordance with the invention wherein the length to thickness ratio of a given panel becomes very large or the overall length of the structure is great, for example, about five panel widths, advantageously one or more tension bands may be placed about the structure to assure tight fitting of the ends of the panels 12.

Although the invention has been described in terms of spline and lapped rabbet joints, advantageously in cases where. particularly rigid and well sealed corner joints are required the lap joints may be replaced with a splined mitre joint. In a similar manner, other conventional joints such as dado and rabbet and the like 'may be employed. Generally, for ease of construction and low cost with satisfactory performance, the lapped rabbet and spline joints are found satisfactory for most installations.

Advantageously, particularly tight seals between the members forming lap joints and butt joints are provided by an extension of the core beyond the facing sheet as illustrated in FIGURE 6. The core material is usually deformable to some extent and any minor irregularities in the face sheets will be filled by the core material when pressure is applied. In the case of butt joints, sufiicient deformation will take place under the pressure excited by the tension members to give core to core contact. Beneficially, a thin resilient gasket may be employed between the joints. Such gasketing generally comprises thin slices of core material, foam rubber, polyethylene, and the like.

By way of further illustration, a number of panels were prepared having one eighth of an inch thick hardboard faces (tempered Masonite made by the Masonite Corporation), and 4 inch thick cores of cellular polystyrene. The face sheets of hardboard were adhered to the foam polystyrene core by means of a phenol formaldehyde resin. The resultant panel had a total weight of 70 pounds. The panels were then grooved and rabbeted as illustrated in the accompanying drawing and assembled into an enclosure substantially as shown in FIGURES 1, 4 and 5. The enclosure had an overall dimension of about 8 feet wide by 12 feet long and 8 feet 4% inches in height. The splines employed to join the panels in edge to edge relationship were about 1 /2 inch by 3 inch by 8 foot strips of expanded cellular polystyrene which were press fit in the panel core grooves 43. The tension members 21, 23 and 25 were 3 by 3 by 0.04 inch galvanized sheet steel. Corner members 62 of FIGURE 7 were prepared from similar galvanized sheet metal. The corners 62 and tension members 21, 23 and 25 were secured by means of sheet metal screws. Sheet metal screws were also used to secure tension members to the panels 12 and 14 at 12 inch intervals. A door opening was cut in one end of the enclosure and an insulated refrigerator door installed. Refrigeration coils and circulating fan were placed within the enclosure and connecting lines were passed through tight fitting openings in the panel. The entire assembly was painted inside and out. Temperatures in the range of about -40 Fahrenheit were maintained within the enclosure for an extended period of time. No damage or undesirable effects were observed after a period of about 2 months.

Although the invention is described with particular reference to generally rectangular structures, which find most frequent application, other configurations are employed with equal facility such as tetrahedral, pyramidal, and prisms such as pentagonal, hexagonal, octagonal, and the like.

What is claimed is:

1. A self-sustaining refrigerated structure which is readily assembled and disassembled comprising in cooperative combination at least 12 generally rectangular panels, said panels comprising a pair of opposed face members having disposed therebetween foamed plastic insulating means, each of said panels having at least three edges provided with a rabbet designed to interfit with a like rabbet, the remaining edge defining a groove within the core of said panel, said groove being disposed therein a spline in a plane generally parallel to a face of said panel, four of said panels being arranged in the form of a hollow rectangular prism having a first end and a second end with the splined sides at the first end of said hollow rectangular prism, a pair of panels positioned within the opening at the second end of said prism having grooved edges abutting and a spline in said grooves, the rabbeted edges of said panels engaging the rabbeted edges of said rectangular prism to form a five sided generally rectangular configuration, a second similar five sided generally rectangular configuration disposed with the grooved edges of its first end in engagement with the grooved edges of the first end of said first five sided configuration and receiving first end of said first five sided configuration, one of said panels defining a passageway from the enclosed space within the panel structure to the space without, an insulated door closing said passageway and elongated external tension members disposed about the periphery of the structure, the elongated tension members providing a compressive force on the structure and providing the sole means to maintain the panels in engagement with each other in the longitudinal direction of the tension members, the tension members being metal angles longitudinally disposed along each of the peripheral edges of the structure and overlying corners formed by adjacent panels, the tension members conforming generally to the external configuration of the refrigerated structure.

2. The enclosure of claim 1, wherein said plastic is a polystyrene.

3. The enclosure of claim 1, wherein said splines are foam plastic splines.

References Cited by the Examiner UNITED STATES PATENTS THERON E. CONDON, Primary Examiner.

R. A. JENSEN, J. R. GARRETT, Assistant Examiners. 

1. A SELF-SUSTAINING REFRIGERATED STRUCTURE WHICH IS READILY ASSEMBLED AND DISASSEMBLED COMPRISING IN COOPERATIVE COMBINATION AT LEAST 12 GENERALLY RECTANGULAR PANELS, SAID PANELS COMPRISING A PAIR OF OPPOSED FACE MEMBERS HAVING DISPOSED THEREBETWEEN FOAMED PLASTIC INSULATING MEANS, EACH OF SAID PANELS HAVING AT LEAST THREE EDGES PROVIDED WITH A RABBIT DESIGNED TO INTERFIT WITH A LIKE RABBET, THE REMAINING EDGE DEFINING A GROOVE WITHIN THE CORE OF SAID PANEL, SAID GROOVE BEING DISPOSED THEREIN A SPLINE IN A PLANE GENERALLY PARALLEL TO A FACE OF SAID PANEL, FOUR OF SAID PANELS BEING ARRANGED IN THE FORM OF A HOLLOW RECTANGULA PRISM HAVING A FIRST END AND A SECOND END WITH THE SPLINE SIDES AT THE FIRST END OF SAID HOLLOW RECTANGULAR PRISM, A PAIR OF PANELS POSITIONED WITHIN THE OPENING AT THE SECOND END OF SAID PRISM HAVING GROOVED EDGES ABUTTING SAID SPLINE IN SAID GROOVES, THE RABBETED EDGES OF SAID PANELS ENGAGING THE RABBETED EDGES OF SAID RECTANGULAR PRISM TO FORM A FIVE SIDED GENERALLY RECTANGULAR CONFIGURATION, A SECOND SIMILAR FIVE SIDED GENERALLY RECTANGULAR CONFIGURATION DISPOSED WITH THE GROOVED EDGES OF ITS FIRST END IN ENGAGEMENT WITH THE GROOVED EDGES OF THE FIRST END OF SAID FIRST FIVE SIDED CONFIGURATION AND RECEIVING FIRST END OF SAID FIRST FIVE SIDED CONFIGUATION, ONE OF SAID PANELS DEFINING A PASSAGEWAY FROM THE ENCLOSED SPACE WITHIN THE PANEL STRUCTURE TO THE SPACE WITHOUT, AN INSULATED DOOR CLOSING SAID PASSAGEWAY AND ELONGATED EXTERNAL TENSION MEMBERS DISPOSED ABOUT THE PERHIPHERY OF THE STRUCTURE, THE ELONGATED TENSION MEMBERS PROVIDING A COMPRESSIVE FORCE ON THE STRUCTURE AND PROVIDING A SOLE MEANS TO MAINTAIN THE PANELS IN ENGAGEMENT WITH EACH OTHER IN THE LONGITUDINAL DIRECTION OF THE TENSION MEMBERS, THE TENSION MEMBERS BEING METAL ANGLES LONGITUDINALLY DISPOSED ALONG EACH OF THE PERIPHERAL EDGES OF THE STRUCTURA AND OVERLYING CORNERS FORMED BY ADJACENT PANELS, THE TENSION MEMBERS CONFORMING GENERALLY TO THE EXTERNAL CONFIGURATION OF THE REFRIGERATED STRUCTURE. 